1. Field of the Invention
In one aspect, the invention relates to automated liquid dispensers and more particularly to automated liquid dispensers that sense the level of a dispensed liquid with respect to the height of a container to be filled to prevent overfilling. In another aspect, the invention relates to a refrigerator incorporating an automated liquid dispenser.
2. Description of the Related Art
Contemporary refrigerators commonly have a water/beverage dispenser located in the door of the refrigerator for the external dispensing of liquid, usually chilled water, from the refrigerator. An ice dispenser often accompanies the liquid dispenser. Illustrative dispensers are shown in U.S. Pat. Nos. 6,425,425; 5,551,598; and 4,807,086, which are incorporated by reference.
Some dispensers are activated via a pressure-sensitive switch that is depressed by a container, such as a cup or glass, when it is inserted into the dispenser. Others employ buttons that a user continuously pushes until the desired amount of water has been dispensed. Both of these systems require a user to remain at the refrigerator to either hold the container in place or to push the buttons during dispensing. Additionally, dispensing can be undesirably interrupted and take longer than necessary if the user is unable to continuously activate the dispenser.
A known problem of such dispensers is that inattentive users can overfill the container, resulting in the spilling of the liquid onto the refrigerator or surrounding floor. It is desirable to provide the dispenser with overfill protection that stops the dispensing of the liquid regardless of the user input.
Overfill protection systems are known and many work fairly well for their intended purpose. Most of the known overfill protection systems rely on a plurality sensors to sense the container height and the liquid level. The use of a plurality of sensors increases the cost of the system. In a commodity market like household refrigerators, the additional cost attributable to the plurality of sensors is highly undesirable. There is a continuous need in this market for properly functioning systems with reduced cost.
In one aspect, the invention relates to an automated liquid dispenser for dispensing a liquid into an open-top container comprising a housing defining a dispensing zone for receiving the open-top of the container, a liquid dispensing spout extending from the housing and above the dispensing zone for dispensing liquid into the container, and first and second reflector arrays disposed on opposite sides of the dispensing zone such that the open-top container is between the first and second arrays when the open-top container is received within the dispensing zone. Each reflector array comprises multiple vertically spaced reflectors, with a reflector on the first array being paired with a reflector on the second array. An emitter is mounted in a position to emit a signal onto the multiple reflectors of the first reflector array for reflection across the dispensing zone and onto the corresponding paired reflectors of the second array, and a receiver is mounted in a position to receive the emitted signal reflected from the reflectors of the second array and generate a container height signal. Additionally, the dispenser comprises a liquid level sensor for determining the liquid level in the container and generating a liquid level signal and a controller coupled to the receiver and the liquid level sensor for controlling the filling of the liquid into the container based on the received container height signal and the liquid level signal.
The first and second reflector arrays can be removably mounted to the housing. Further, the first reflector array can be carried by a first panel and the second reflector array can be carried by a second panel, wherein the first and second panels are removably coupled to the housing. The reflectors can be integrally formed with the panels and are preferably molded from a thermal plastic material.
The reflectors are disposed at a predetermined angle relative to a plane orthogonal to the emitted signal such that the emitted signal is reflected from the reflectors of the first array horizontally across the dispensing zone, onto the paired reflectors of the second array, and then onto the receiver. The predetermined angle for the reflectors of the first array is preferably 45-degrees relative to a plane orthogonal to the emitted signal, and the predetermined angle for the reflectors of the second array is preferably xe2x88x9245 degrees relative to a plane orthogonal to the emitted signal.
The reflectors in each array are arranged in a step configuration with a vertical offset and a lateral offset between adjacent reflectors, wherein the vertical offset can be between 0.75 and 2 inches and the lateral offset can be 0.25 to 1.00 inches.
The liquid level sensor is a wide bandwidth transducer, such as a piezo film or a micro-electro-mechanical system (MEMS).
The container height signal is composite signal of all the signals reflected across the dispensing zone and not blocked by the open-top container.
In another aspect, the invention relates to a refrigerator in combination with a liquid dispenser for dispensing a liquid into an open-top container, wherein the refrigerator comprises a cabinet having at least one refrigerated compartment with an open face and a door movably mounted to the refrigerated compartment for movement between a closed position, where the door covers the open face, and an open position, where the door is withdrawn from the open face. The liquid dispenser in combination with the refrigerator comprises a housing located in a recess in the door and defining a dispensing zone for receiving the open-top of the container. A liquid dispensing spout extends from the housing and above the dispensing zone for dispensing liquid into the container. First and second reflector arrays are disposed on opposite sides of the dispensing zone such that the open-top container is between the first and second arrays when the open-top container is received within the dispensing zone, and each reflector array comprises multiple vertically-spaced reflectors, with a reflector on the first array being paired with a reflector on the second array. An emitter is mounted in a position to emit a signal onto the multiple reflectors of the first reflector array for reflection across the dispensing zone and onto the corresponding paired reflectors of the second array, and a receiver is mounted in a position to receive the emitted signal reflected from the reflectors of the second array and generate a container height signal. Additionally, the dispenser comprises a liquid level sensor for determining the liquid level in the container and generating a liquid level signal and a controller coupled to the receiver and the liquid level sensor for controlling the filling of the liquid into the container based on the received container height signal and the liquid level signal.
The first and second reflector arrays can be removably mounted to the housing. Furthermore, the first reflector array can be carried by a first panel and the second reflector array can be carried by a second panel, wherein the first and second panels are removably coupled to the housing. The housing comprises opposing sides, with each side having a channel, and the panels are received within the channels to mount the panels to the housing. The reflectors can be integrally formed with the panels and are preferably molded from a thermal plastic material.
The housing further comprises an upper wall spanning the side walls, and the emitter, receiver, and liquid level sensor are mounted to the upper wall. The dispensing spout extends through the upper wall.
The reflectors are disposed at a predetermined angle relative to a plane orthogonal to the emitted signal such that the emitted signal is reflected from the reflectors of the first array horizontally across the dispensing zone, onto the paired reflectors of the second array, and then onto the receiver. The predetermined angle for the reflectors of the first array is preferably 45 degrees relative to a plane orthogonal to the emitted signal, and the predetermined angle for the reflectors of the second array is preferably xe2x88x9245 degrees relative to a plane orthogonal to the emitted signal.
The reflectors in each array are arranged in a step configuration with a vertical offset and a lateral offset between adjacent reflectors. The vertical offset can be between 0.75 and 2 inches, and the lateral offset can be 0.25 to 1.00 inches.
The liquid level sensor is a wide bandwidth transducer, such as a piezo film or a micro-electro-mechanical system (MEMS).
The container height signal is composite signal of all the signals reflected across the dispensing zone and not blocked by the open-top container.